card sleeves dragon shield | Standard Size Matte | 100 CT - Smooth & Tough Premium TCG Sleeves Comes with 60 Japanese size card sleeves for trading cards measuring up to 59x86 mms (2 Dragon Shield: MTG Guildpact Series

The question if it was ever intended to be included in packs is not completely clear, but the discovery of E4 member styluspt that the cards was actually advertised to be in the set in a Japanese Trainers Magazine as well as on early concept designs of Jungle booster packs certainly makes this appear likely (see PIKACHU 1ST ED JUNGLE BLACK STAR PROMO - WAS IT INTENTIONAL

As described, this is functioning as intended

Card values are likely to fluctuate heavily over time, but the launch of the expansion in local game stores is as good a time as any to look at the market

Ultimately, the key to building an awesome and valuable card collection is staying informed, cautious, and connected